1. Field of the Invention
The present invention relates to a surgical cutting device, and, more particularly, to a rotary surgical cutting device.
2. Description of the Related Art
Cutters and reamers are used in surgical procedures to prepare canals in bone material to receive implants. The cutters and reamers generally have a hemispherical or cylindrical cutting head. This head is often fixed to the end of a shaft for rotatably driving the cutting head.
An orthopaedic reamer is used to cut a bone and thereby form the interior of the bone into a predetermined shape for receiving an orthopaedic implant. For example, an intramedullary (IM) reamer may be placed into the intramedullary canal of the bone and used to ream the interior of the bone to receive the stem of an orthopaedic implant. Such a reamer includes a radial, peripheral surface which generally includes a plurality of radially extending teeth for cutting the bone in a radial direction as the reamer proceeds in an axial direction into the bone. The size of the opening formed in the bone is determined by the outside diameter of the reamer.
An orthopaedic reamer may also include a cutting head with a distal face which has a plurality of cutting teeth formed therein. The distal face has a shape which corresponds to the shape of an orthopaedic implant to be received within the bone, and includes a plurality of cutting teeth extending from the distal face. The reamer is placed against the bone surface to be cut, such as an acetabulum or glenoid, and is plunge cut into the bone. Such reamers are effective for removing a portion of the bone so that the bone is shaped to receive the implant.
An orthopaedic reamer including a distal face as described above may include cutting teeth which are formed by a punching operation for each individual tooth. Each cutting tooth typically includes a hole and a raised portion which extends from the distal face. The raised portion includes a humped or center portion which results in the bone being cut with an annular groove as the cutting head is rotated about its rotational axis. In other words, each cutting tooth includes a raised portion resembling half of a cone split longitudinally, with the base edge of the cone defining the cutting edge. Although such a cutting tooth configuration is effective to remove the bone for receiving an implant, the rough surface resulting from the cutting teeth may not be desirable for certain applications.
IM reamers typically include an axial cutting face and peripheral fluted cutting teeth. Such reamers can be cylindrical or bullet shaped with multiple cutting flutes along the surface extending from the leading tip. The cutting flutes are oriented with the long axis at a low angle or a helix. Flutes are generally shallow and can become clogged with cutting debris. The cutting work in the bone wall has the affect of forming bone chips, which mixes with other matter in the bone. The rotation of the reamer along with the bone chips and debris may cause heating in the bone that can lead to thermalnecrosis of the bone.
What is needed in the art is a reamer that leaves a smooth cut surface with minimal impact on the bone structure.